Vibration damping device

Abstract

It exhibits excellent vibration damping performance regardless of the mass of the load placed on top. [Solution] The vibration damping device 10 is attached to a rack 1 on which luggage can be stored, and comprises a base member 11 attached to a support member 6 of the rack 1 that extends in a first horizontal direction DH1 and supports the luggage from below, a loading platform member 12 provided above the base member 11 on which luggage is placed, and a rail 13 fixed to the base member 11 and provided to extend in a first horizontal direction DH1, with a rail surface formed such that the upper surface 13c is recessed downward in an arc shape when viewed from a second horizontal direction DH2 perpendicular to the first horizontal direction DH1, the loading platform member 12 is provided with a contact portion 14 that contacts the rail surface from above, and the loading platform member 12 is provided so as to be movable relative to the base member 11 in the first horizontal direction DH1 while maintaining the state in which the contact portion 14 contacts the rail surface.

Description

Technical Field

[0001] The present invention relates to a vibration damping device dedicated to a rack attached to a rack capable of storing luggage.

Background Art

[0002] A vibration damping device called a TMD (tuned mass damper) may be provided in a structure such as a high-rise building. The TMD is composed of a mass tuned to a specific vibration frequency (resonance frequency) and springs and dampers that support it. This device has the effect of suppressing the vibration of the structure against dynamic external forces such as earthquakes and winds. For example, Patent Document 1 discloses a vibration damping device in which the upper end of a suspension member is attached to a support structure and the lower end of the suspension member is attached to a mass body.

[0003] By the way, for example, in an automated warehouse or the like, luggage is stored in a rack. In particular, when luggage is stored in a rack by a stacker crane or the like, the rack is arranged such that the storage space for the luggage has a plurality of stages in the vertical direction and a plurality of rows in the width direction, and luggage is taken in and out of the storage space by a stacker crane or the like from one side in the depth direction. Therefore, the rack has a length corresponding to only one storage space in the depth direction and has a short configuration. For this reason, when an earthquake or the like occurs, a vibration damping device such as the above TMD may be provided for the purpose of suppressing the vibration in the depth direction of the rack.

[0004] In the rack as described above, a support member is often provided in each storage space so as to be supported by a column of the rack and extend in the depth direction. In each storage space, the luggage is placed and supported on this support member, so that the luggage is stored in the rack. Patent Document 2 discloses a vibration damping device configured to be installed on such a support member. More specifically, the vibration damping device of Patent Document 2 includes a base member that extends horizontally on the rack and supports the load from below, and is fixed to the support member; a slide member that is positioned on the base member, has a load on its upper surface, and is slidable relative to the base member in a direction parallel to the base member; a damper device that extends in a direction parallel to the support member so as to be expandable and contractible; and a spring member that extends in a direction parallel to the support member so as to be expandable and contractible. The damper device has one end connected to the base member and the other end connected to the slide member, and the spring member has one end fixed to the base member and the other end connected to the slide member. In the vibration damping device described in Patent Document 2, the load also serves as the mass, allowing the vibration damping device to have a compact configuration.

[0005] In realizing a vibration damping device as described in Patent Document 2, it is desirable to synchronize the vibration period of the vibration damping device with the natural period in the depth direction of the rack in order to efficiently achieve vibration damping performance. However, since various types of cargo can be stored in each storage space of the rack, the mass of the cargo as a mass body can vary. As a result, the vibration period of the vibration system, which is composed of springs, damping, and mass, changes according to the value of the mass, making it difficult to set the period of the vibration damping device to a constant value. Consequently, it may not be possible to sufficiently synchronize the period of the vibration damping device with the natural period of the rack, and as a result, the vibration damping performance may not be efficiently achieved. In this regard, for example, Patent Document 3 discloses a vibration damping device provided on a rack for supporting pallets. This vibration damping device comprises a slidably supported additional mass, a damper that generates a damping force in the sliding direction of the additional mass, and a fixing jig that fixes the additional mass and the damper to the rack. The fixing jig is fixed to the pallet mounting portion of the rack, slidably supports the additional mass, and transmits the damping force of the damper to the rack. In the rack vibration damping device described in Patent Document 3, an additional mass is provided, and the mass of this additional mass is made large to support the rack in a state that is not in tune with the rack's natural frequency, and a damper is used to provide a large damping performance, thereby eliminating the need for frequency tuning. However, in such a configuration, the vibration damping performance may not be as efficient as when the vibration damping device is configured to synchronize its period with the rack's natural period.

[0006] There is a need for a vibration damping device that can be mounted on a rack and exhibit good vibration damping performance regardless of the mass of the load placed on it. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2014-228131 [Patent Document 2] Japanese Patent Publication No. 2020-128276 [Patent Document 3] Japanese Patent Publication No. 2013-180870 [Overview of the project] [Problems that the invention aims to solve]

[0008] The problem that this invention aims to solve is to provide a vibration damping device that can be attached to a rack and can exhibit good vibration damping performance regardless of the mass of the load placed on it. [Means for solving the problem]

[0009] The inventors have created a vibration damping device specifically for racks. This device involves attaching a loading platform member to the upper end surface of a support member (rack) via a base member, and fixing an arc-shaped rail to the base member, allowing the loading platform member to move relative to the base member. A key feature of this vibration damping device is that, in accordance with the principle of a pendulum, the arc-shaped rail is fixed to the base member, and the loading platform member is moved along the rail, so that the period of the TMD is not affected even if the weight of the load changes. To solve the above problems, the present invention employs the following means. That is, the present invention provides a vibration damping device that can be attached to a rack capable of storing luggage, comprising: a base member attached to a support member of the rack that extends in a first horizontal direction and supports the luggage from below; a loading platform member provided above the base member on which the luggage is placed; and a rail fixed to the base member and provided to extend in the first horizontal direction, with a rail surface formed such that when viewed from a second horizontal direction perpendicular to the first horizontal direction, the upper surface is recessed downward in an arc shape, wherein the loading platform member has a contact portion that contacts the rail surface from above, and the loading platform member is provided so as to be movable relative to the base member in the first horizontal direction while maintaining the state in which the contact portion contacts the rail surface. In the configuration described above, the rack is equipped with a support member extending in the first horizontal direction, and the vibration damping device is equipped with a base member attached to the support member and a loading platform member provided above the base member. In this configuration, the cargo is placed on the loading platform member, and the load of the cargo is transmitted to the support member via the loading platform member and the base member, thereby supporting the cargo from below by the support member. In addition to the above configuration, the vibration damping device includes a rail fixed to the base member, extending in a first horizontal direction, with a rail surface formed on its upper surface, and the loading platform member has a contact portion that contacts the rail surface from above. Furthermore, the loading platform member is provided so as to be movable relative to the base member in the first horizontal direction while maintaining the state in which the contact portion contacts the rail surface. Therefore, when an earthquake or the like occurs and the rack vibrates in the first horizontal direction, the base member attempts to move in the first horizontal direction together with the support member, while the loading platform member and the load placed on it move relative to the base member in the first horizontal direction due to inertial force. In this way, the load acts as a mass and applies a force from the load to the rack that is opposite to the rack's response speed, thereby damping the rack's vibration. Here, the rail surface is formed such that, when viewed from a second horizontal direction perpendicular to the first horizontal direction, the upper surface is curved downwards in an arc shape. Therefore, when an earthquake or the like occurs and the rack vibrates in the first horizontal direction, the loading platform member moves relative to the base member while maintaining contact with the rail surface. As a result, the loading platform member and the load placed on it perform a pendulum motion based on the arc shape of the rail surface. The period of this pendulum motion does not depend on the mass of the load, but is determined only by the radius of the pendulum motion. In other words, the period of movement of the load can be kept constant regardless of the mass of the load placed on the loading platform member. Therefore, by adjusting the radius of the pendulum motion to roughly synchronize the period of movement of the load with the natural period of the rack in the first horizontal direction, it is possible to achieve good vibration damping performance. In this way, it becomes possible to realize a vibration damping device that can be attached to a rack and exhibit good vibration damping performance regardless of the mass of the load placed on it.

[0010] Furthermore, the present invention provides a vibration damping device that can be attached to a rack capable of storing luggage, comprising: a base member attached to a support member of the rack that extends in a first horizontal direction and supports the luggage from below; a loading platform member provided above the base member on which the luggage is placed; and a rail fixed to the loading platform member and provided to extend in the first horizontal direction, with a rail surface formed such that when viewed from a second horizontal direction perpendicular to the first horizontal direction, the lower surface is recessed upward in an arc shape, wherein the base member has a contact portion that contacts the rail surface from below, and the loading platform member is provided so as to be movable relative to the base member in the first horizontal direction while maintaining a state in which the rail surface is in contact with the contact portion of the base member. In the configuration described above, the rack is equipped with a support member extending in the first horizontal direction, and the vibration damping device is equipped with a base member attached to the support member and a loading platform member provided above the base member. In this configuration, the cargo is placed on the loading platform member, and the load of the cargo is transmitted to the support member via the loading platform member and the base member, thereby supporting the cargo from below by the support member. In addition to the above configuration, the vibration damping device includes a rail fixed to the loading platform member, extending in a first horizontal direction, with a rail surface formed on its lower surface, and the base member has a contact portion that abuts against the rail surface from below. Furthermore, the loading platform member is provided so as to be movable relative to the base member in the first horizontal direction while maintaining the state in which the rail surface abuts against the contact portion of the base member. Therefore, when an earthquake or the like occurs and the rack vibrates in the first horizontal direction, the base member attempts to move in the first horizontal direction together with the support member, while the loading platform member and the load placed on it move relative to the base member in the first horizontal direction due to inertial force. In this way, the load acts as a mass and applies a force from the load to the rack that is opposite to the rack's response speed, thereby damping the rack's vibration. Here, the rail surface is formed such that, when viewed from a second horizontal direction perpendicular to the first horizontal direction, the lower surface is curved upward in an arc shape. Therefore, when an earthquake or the like occurs and the rack vibrates in the first horizontal direction, the contact portion of the base member remains in contact with the rail surface, and the loading platform member moves relative to the base member. As a result, the loading platform member and the load placed on it perform a pendulum motion based on the arc shape of the rail surface. The period of this pendulum motion does not depend on the mass of the load, but is determined only by the radius of the pendulum motion. In other words, no matter what mass the load has when placed on the loading platform member, the period of movement of the load can be kept constant. Therefore, by adjusting the radius of the pendulum motion to roughly synchronize the period of movement of the load with the natural period of the rack in the first horizontal direction, it is possible to achieve good vibration damping performance. In this way, it becomes possible to realize a vibration damping device that can be attached to a rack and exhibit good vibration damping performance regardless of the mass of the load placed on it.

[0011] In one embodiment of the present invention, the first horizontal direction is the depth direction of the rack, and when the rack vibrates in the first horizontal direction, the loading platform member moves relative to the base member so as to reciprocate in the first horizontal direction, and the radius of curvature of the rail surface is set such that the period of the reciprocation is approximately equal to the natural period of the rack in the first horizontal direction. While racks tend to vibrate more in the depth direction (where the length is shorter than the width direction), with the above configuration, the first horizontal direction is the depth direction of the rack, and when the rack vibrates in the first horizontal direction, the loading platform member moves relative to the base member in a reciprocating motion in the first horizontal direction. Therefore, the vibration damping device can efficiently suppress vibrations of the rack in the depth direction. In addition, since the radius of curvature of the rail surface is set such that the reciprocating cycle as described above is approximately equal to the natural period in the first horizontal direction of the rack, the period of the vibration damping device is substantially synchronized with the natural period in the depth direction of the rack. Therefore, the vibration damping device can more efficiently suppress the vibration in the depth direction of the rack.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a vibration damping device attached to a rack that can exhibit good vibration damping performance regardless of the mass of the load placed thereon.

Brief Description of the Drawings

[0013] [Figure 1] It is a front view of a rack in which a vibration damping device according to an embodiment of the present invention is provided. [Figure 2] It is a plan view of an automatic warehouse provided with the above rack. [Figure 3] It is a cross-sectional view of the rack shown on the upper side in FIG. 2, and is a cross-sectional view of the portion taken along the arrow I-I in FIG. 1. [Figure 4] It is an enlarged view of the portion taken along the arrow A in FIG. 3, and is a plan view of the vibration damping device in a state where it is provided on the above rack. [Figure 5] It is a cross-sectional view of the portion taken along the arrow II-II regarding the vibration damping device provided on the left side in FIG. 4. [Figure 6] It is a cross-sectional view of the portion taken along the arrow III-III in FIG. 5. [Figure 7] It is an exploded view of the vibration damping device shown in FIG. 6. [Figure 8] It is an exploded perspective view of the vibration damping device shown in FIG. 6. [Figure 9] It is a diagram showing a model when performing seismic response analysis on a rack provided with the vibration damping device of the above embodiment. [Figure 10] It is a graph showing the response acceleration of each layer of the rack as a result of performing seismic response analysis on the model shown in FIG. 9. [Figure 11]Figure 9 shows a graph illustrating the relative displacement of pallets in each layer of the rack, based on the results of seismic response analysis performed on the model shown. [Figure 12] Figure 9 shows a graph illustrating the response acceleration acting on the cargo placed on the pallets in each layer of the rack, based on the results of seismic response analysis performed on the model shown. [Figure 13] This is a longitudinal cross-sectional view of a vibration damping device according to the first modified embodiment described above. [Figure 14] This is a plan view of a vibration damping device according to a second modified example of the above embodiment. [Figure 15] This is a schematic longitudinal cross-sectional view of the vibration damping device located on the left side in Figure 14. [Figure 16] This is a side view of the vibration damping device located on the left side in Figure 14, as seen from the side of the luggage storage space (the right side in Figure 14). [Figure 17] This is a cross-sectional view of the area indicated by the arrow IV-IV in Figure 15. [Figure 18] This is an enlarged view of the main part of the vibration damping device according to the third modified embodiment described above. [Modes for carrying out the invention]

[0014] The present invention is a vibration damping device specifically for racks, and is configured, for example, as shown in Figure 8, to include a base member attached to a support member of a rack that supports cargo from below, a loading platform member provided above the base member on which the cargo is placed, and an arc-shaped rail fixed to the base member or the loading platform member, wherein the loading platform member is provided to be movable relative to the base member in the depth direction of the rack. Furthermore, the vibration damping device includes a damping mechanism that absorbs the vibration energy of the rack when the loading platform member moves, with each end constituting the damper fixed to the base member and the loading platform member, and a restoring force mechanism using rails. Embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 is a front view of a rack on which the vibration damping device in this embodiment is installed. Figure 2 is a plan view of the automated warehouse on which the rack is installed. Figure 3 is a cross-sectional view of the rack shown at the top in Figure 2, and is a cross-sectional view of the portion indicated by arrow II in Figure 1. Rack 1 is configured to store luggage. Rack 1 comprises column members 2, beam members 3, bracket members 5, and support members 6. The column members 2 are erected on the floor surface F. The column members 2 extend in the vertical direction DV. In this embodiment, the column members 2 are formed from steel pipes with a rectangular cross-section. Multiple column members 2 are provided at intervals in the first horizontal direction DH1. In this embodiment, two, i.e., a pair of column members 2, are provided in the first horizontal direction DH1. Multiple column members 2 are also provided at intervals in the second horizontal direction DH2, which is perpendicular to the first horizontal direction DH1 in the horizontal plane. The beam members 3 are provided to extend in the first horizontal direction DH1 and the second horizontal direction DH2. The beam members 3 are erected between adjacent column members 2. In this embodiment, the beam members 3 are formed from steel pipes with a rectangular cross-section. The beam members 3 are provided at regular intervals in the vertical direction DV.

[0015] The bracket 5 is joined to each of the column members 2. In this embodiment, the bracket 5 is formed from a steel pipe with a rectangular cross-section. If there is another column member 2 adjacent to each of the column members 2 in the second horizontal direction DH2, the bracket 5 is provided so as to extend from the column member 2 toward the adjacent column member 2 in the second horizontal direction DH2 and then terminate. The bracket 5 is joined to each of the pair of column members 2 in the first horizontal direction DH1, so that they are provided as a pair in the first horizontal direction DH1. For each of the column members 2, the brackets 5 are provided at regular intervals in the vertical direction DV.

[0016] The support member 6 is installed between the tips of the arms 5, which are provided as a pair in the first horizontal direction DH1, and extends in the first horizontal direction DH1. The support member 6 is formed to have a rectangular shape when viewed from the first horizontal direction DH1. In this embodiment, the support member 6 is made of a steel pipe with a rectangular cross-section. Similar to the arms 5, the support members 6 are provided at regular intervals in the vertical direction DV. As shown in Figure 5, which will be used later, the support member 6 comprises an upper plate 6c, a lower plate 6d, and a pair of side plates 6e. The upper plate 6c and the lower plate 6d are provided extending within the horizontal plane formed by the first horizontal direction DH1 and the second horizontal direction DH2. The upper plate 6c is located above the lower plate 6d, and the upper plate 6c and lower plate 6d are provided spaced apart from each other in the vertical direction DV. Each of the pair of side plates 6e is provided so as to connect the ends of the upper plate 6c and the lower plate 6d, which are located at the ends in the second horizontal direction DH2 and extend in the direction of the first horizontal direction DH1, in an upward and downward direction.

[0017] As described above, the support members 6 are provided at regular intervals in the vertical direction DV. A storage space S for storing luggage 100 is formed between these support members 6, which are spaced apart in the vertical direction DV, and between adjacent column members 2 in the second horizontal direction DH2. In each storage space S, the support members 6 are provided as a pair, spaced apart from each other in the second horizontal direction DH2. The luggage 100 is placed on the pair of support members 6 so as to span across the second horizontal direction DH2 between them, and is supported from below by each of the pair of support members 6. In this view, the support members 6 are used as so-called support rails. In this way, in rack 1, multiple storage spaces S are arranged in the second horizontal direction DH2 to form a single layer, and multiple such layers are stacked in the vertical direction DV. In the first horizontal direction DH1, only one storage space S is provided. Therefore, in this embodiment, the first horizontal direction DH1 is the depth direction of rack 1, and the second horizontal direction DH2 is the width direction.

[0018] In this embodiment, the racks 1 described above are provided as a pair of two units. Between the pair of racks 1, a stacker crane rail 8, on which a stacker crane (not shown) travels, is provided, extending in the second horizontal direction DH2. As shown in Figure 6, which will be used in later explanation, the cargo 100 consists of a cargo body 102, which is the actual item to be stored in the rack 1, and a pallet 101 on which the cargo body 102 is placed. The stacker crane transports the cargo 100 by traveling along the stacker crane rail 8 while gripping the pallet 101 with forks or the like. The stacker crane loads and unloads the cargo 100 into and out of the storage space S by inserting forks or the like into the storage space S. For this reason, an opening is formed on the side of the rack 1 that faces the stacker crane rail 8. Hereafter, we will describe the rack 1 shown on the upper side of Figure 2. In Figure 2, the upper rack 1 has a stacker crane rail 8 on its lower side, so the above-mentioned opening is formed on the lower side of Figure 2, and forks, etc., are inserted from the lower side to the upper side.Hereafter, the side of the rack 1 in the first horizontal direction DH1 into which the opening forks, etc., are inserted will be referred to as the front side FS, and the side opposite to the front side FS in the first horizontal direction DH1 will be referred to as the back side BS.

[0019] As described above, rack 1 has a shape in which the length in the first horizontal direction DH1 (depth direction) is shorter than the length in the second horizontal direction DH2 (width direction). Therefore, when an earthquake occurs, rack 1 is particularly susceptible to vibration in the first horizontal direction DH1. To suppress such vibration in the first horizontal direction DH1, a vibration damping device is installed on rack 1. Figure 4 is an enlarged view of the section indicated by arrow A in Figure 3, and is a plan view of the vibration damping device installed on the rack. Figure 5 is a cross-sectional view of the section indicated by arrow II-II relating to the vibration damping device installed on the left side in Figure 4. Figure 6 is a cross-sectional view of the section indicated by arrow III-III in Figure 5. Figure 7 is an exploded view of the vibration damping device shown in Figure 6. Figure 8 is an exploded perspective view of the vibration damping device shown in Figure 6. The vibration damping device 10 is provided for each of the pair of support members 6 that form a single storage space S. The vibration damping device 10 differs in shape between the vibration damping device 10A, which is provided on the support member 6A located on the left side when viewed from the front side FS, and the vibration damping device 10B, which is provided on the support member 6B located on the right side. Therefore, the vibration damping device 10A on the left side will be described in detail below, and then the differences between the vibration damping device 10B on the right side and the vibration damping device 10A will be described.

[0020] The vibration damping device 10A comprises a base member 11, a loading platform member 12, a rail 13, and a damper 17. The base member 11 is a long member that extends in the first horizontal direction DH1. The base member 11 comprises an upper plate 11c, a pair of side plates 11e, a first extension plate 11f, and a second extension plate 11g. The base member 11 is shaped such that the above-mentioned upper plate 11c, pair of side plates 11e, first extension plate 11f, and second extension plate 11g can be formed by bending, for example, a single steel plate. Specifically, when viewed from the front side FS, the upper plate 11c is provided to extend in the second horizontal direction DH2. Each of the pair of side plates 11e is formed to extend downward from each of the ends of the upper plate 11c that are opposite each other in the second horizontal direction DH2. From the perspective that a single storage space S is formed by the pair of support members 6, when viewed from the front side FS, with respect to the vibration damping device 10A located on the left side, the side plate 11e located on the left side is located further outward than the side plate 11e located on the right side. The first extension plate 11f is provided so as to rise further outward (to the left) from the lower end of this outer (left) side plate 11e in the second horizontal direction DH2. The second extension plate 11g is provided so as to rise upward from the end of the first extension plate 11f that is opposite to the side plate 11e.

[0021] On the outer side plate 11e of the base member 11, where the first extension plate 11f is provided, a rectangular notch 11h is formed at the front end 11a of the side plate FS, extending upward from the lower end of the side plate 11e. A damper fixing member 11i is attached to the upper surface of the first extension plate 11f of the base member 11, near the end 11b of the rear side BS, for which a damper 17, which will be described later, will be attached. The base member 11 is further equipped with an anti-slip material 11j. The anti-slip material 11j is made of, for example, rubber. The anti-slip material 11j is attached to the lower surface of the upper plate 11c.

[0022] The cargo bed member 12 is a long member that extends in the second horizontal direction DH2. The cargo bed member 12 comprises an upper plate 12c and a pair of side plates 12e. The cargo bed member 12 is shaped such that the upper plate 12c and a pair of side plates 12e can be formed by bending, for example, a single steel plate. Specifically, when viewed from the front side FS, the upper plate 12c is provided to extend in the second horizontal direction DH2. Each of the pair of side plates 12e is formed to extend downward from each of the ends of the upper plate 12c that are opposite each other in the second horizontal direction DH2.

[0023] Each of the pair of side plates 12e of the cargo bed member 12 has an elongated hole 12h that extends in the first horizontal direction DH1. In this embodiment, each of the pair of side plates 12e has one elongated hole 12h at the front end 12a and one at the rear end 12b. In each of the pair of side plates 12e, the elongated holes 12h are located at the same position in the first horizontal direction DH1. On the outer surface of the side plate 12e of the cargo bed member 12 (the left side when viewed from the front side FS), a damper fixing member 12i is attached near the end 12a on the front side FS side, for which a damper 17, which will be described later, will be attached.

[0024] The cargo bed member 12 is provided with a contact portion 14 that abuts against the rail 13, which will be described next. In this embodiment, the contact portion 14 is a linear member 14A that extends linearly in the second horizontal direction DH2. In particular, in this embodiment, the linear member 14A is a shoulder bolt. The linear member 14A has a circular cross-section and comprises a shaft portion 14a that extends in the axial direction, and a head portion 14b formed at one end of the shaft portion 14a so as to enlarge the diameter of the shaft portion 14a. The linear member 14A has a head 14b that is inserted in the second horizontal direction DH2 through each of the elongated holes 12h formed in each of the pair of side plates 12e of the cargo bed member 12. A nut 15 is screwed onto the other end of the linear member 14A, opposite to the head 14b, so as to allow the linear member 14A to roll in the elongated hole 12h. In this way, the pair of side plates 12e are sandwiched from the outside by the head 14b of the linear member 14A and the nut 15. The contact portion 14 is provided for each of the elongated holes 12h located on both ends 12a and 12b of the cargo bed member 12. Therefore, in this embodiment, two contact portions 14 are provided.

[0025] The rail 13 is formed, for example, from a steel plate having a predetermined thickness. As will be described later, the loading platform member 12 is installed from above the base member 11 so as to fit over the base member 11. At this time, the rail 13 is joined to the surface of the side plate 11e of the base member 11 at a position corresponding to the elongated hole 12h of the loading platform member 12 in the first horizontal direction DH1. Therefore, in this embodiment, the rail 13 is provided at a total of four locations: at the front end FS 11a and the rear end BS 11b of each of the pair of side plates 11e. The rail 13 is positioned to extend within a vertical plane formed by the first horizontal direction DH1 and the vertical direction DV, and is joined and fixed to the side plate 11e of the base member 11. The rail 13 is provided such that its upper surface 13c extends in the first horizontal direction DH1. On the rail 13, for example as shown in Figure 7, the rail surface is formed such that the upper surface 13c is recessed downward in an arc shape when viewed from the second horizontal direction DH2. More specifically, the upper surface 13c of the rail 13 is formed to follow the arc of a circle drawn in the plane formed by the first horizontal direction DH1 and the vertical direction DV, with a point located a certain distance above the center of the upper surface 13c in the first horizontal direction DH1. The height of the rail 13 is adjusted so that the entire upper surface 13c protrudes above the upper plate 11c of the base member 11. A sliding material 13k made of polytetrafluoroethylene or the like is attached to the surface of the rail 13 opposite to the side plate 11e.

[0026] The loading platform member 12 described above is provided so as to be placed over the base member 11 and the rails 13 joined to the base member 11 from above. Specifically, the loading platform member 12 is positioned such that the inner surfaces of the top plate 12c and the pair of side plates 12e of the loading platform member 12 face each other's surfaces of the top plate 11c and the pair of side plates 11e of the base member 11. The contact portion 14 of the loading platform member 12, i.e., the linear member 14A, is positioned so that the extension direction of its shaft portion 14a is perpendicular to the first horizontal direction DH1, which is the extension direction of the rails 13. The linear member 14A is provided so as to straddle the pair of rails 13 which are spaced apart in the second horizontal direction DH2 and rest on the upper surfaces 13c of each of the pair of rails 13. In this way, the contact portion 14, which is the linear member 14A, contacts the upper surface 13c (rail surface) of the rails 13 from above. The side plates 12e of the cargo bed member 12 are positioned such that their inner surfaces either contact the sliding material 13k of the rail 13 or are separated by a small gap. In this way, the cargo bed member 12 is positioned such that the base member 11 is sandwiched between the side plates 12e.

[0027] As will be explained later, the cargo bed member 12 is provided so as to be movable relative to the base member 11 in the first horizontal direction DH1. Therefore, when an earthquake occurs and the rack 1 vibrates in the first horizontal direction DH1, the cargo bed member 12 vibrates in the first horizontal direction DH1 relative to the base member 11. The damper 17 is provided interposed between the base member 11 and the cargo bed member 12 to suppress this vibration. In this embodiment, the damper 17 is an oil damper. One end 17a of the damper 17 is joined to the damper fixing member 12i of the cargo bed member 12. The other end 17b of the damper 17 is joined to the damper fixing member 11i of the base member 11. In this way, the damper 17 is positioned above the first extension plate 11f of the base member 11. The first extension plate 11f and the second extension plate 11g of the base member 11 function as oil receiving sections that receive damper oil leaking from the damper 17.

[0028] The vibration damping device 10A described above is installed and attached to the support member 6A, which is located on the left side when viewed from the front side FS, with the base member 11 placed over it from above. Specifically, the base member 11 is positioned such that the inner surfaces of the top plate 11c and the pair of side plates 11e of the base member 11 face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces, which face each other's surfaces. In this way, the base member 11 is installed so that the support member 6 is sandwiched between the side plates 11e. Furthermore, the base member 11 is positioned such that the bracket 5 is housed inside the notch 11h formed in the side plate 11e on the outside of the base member 11 (the left side when viewed from the front side FS). With this configuration, movement of the base member 11 relative to the support member 6 in the first horizontal direction DH1 and the second horizontal direction DH2 is suppressed.

[0029] In Figure 4, the right-side vibration damping device 10B, which is provided on the right-side support member 6B, has a structure symmetrical to that of the vibration damping device 10A in the second horizontal direction DH2. More specifically, in the vibration damping device 10B, the first extension plate 11f, the second extension plate 11g, and the damper 17 provided above them are located on the right side of the vibration damping device 10B when viewed from the front side FS. In configurations other than those described above, the vibration damping device 10B is the same as the vibration damping device 10A.

[0030] Thus, in both vibration damping devices 10A and 10B, the first extension plate 11f, the second extension plate 11g, and the damper 17 are positioned on the outside when viewed as a whole in a single storage space S. In other words, they are not located on the inside, i.e., between the pair of support members 6, and the components of vibration damping devices 10A and 10B are configured to protrude as little as possible between the pair of support members 6. As a result, even if vibration damping devices 10A and 10B are installed on the support members 6A and 6B, the narrowing of the space between the support members 6A and 6B is suppressed, and contact between the vibration damping devices 10A and 10B when the forks of the stacker crane load and unload cargo 100 into and out of the storage space S is suppressed.

[0031] With respect to the vibration damping devices 10A and 10B as described above, the cargo 100 is placed on the upper plate 12c of the respective loading platform members 12 of the vibration damping devices 10A and 10B, straddling the vibration damping devices 10A and 10B. In each of the vibration damping devices 10A and 10B, the load of the cargo 100 is transmitted to the support members 6A and 6B in order via the loading platform member 12 and contact portion 14, rail 13, and base member 11.

[0032] When an earthquake occurs and the rack 1 equipped with the vibration damping device 10 (10A, 10B) described above vibrates in the first horizontal direction DH1, the support members 6 (6A, 6B) are displaced in the first horizontal direction DH1, and the base member 11, whose movement relative to the support members 6 is suppressed, and the rail 13 joined to the base member 11 are also displaced in the first horizontal direction DH1 together with the support members 6. On the other hand, when a load 100 is placed on top of the loading platform member 12, its inertial force causes it to move relative to the base member 11 in the first horizontal direction DH1, in the opposite direction to the direction in which the base member 11 is trying to move.

[0033] Here, the loading platform member 12 is configured to be mounted on the rail 13 via a contact portion 14, i.e., a linear member 14A, with a circular cross-section shaft portion 14a. Furthermore, the linear member 14A is positioned so that the extension direction of the shaft portion 14a is perpendicular to the first horizontal direction DH1, which is the extension direction of the rail 13, and is mounted so as to rest on the upper surfaces 13c of each of the pair of rails 13. At the upper and lower ends of such a linear member 14A, forces acting in opposite directions in the first horizontal direction DH1 are exerted by the loading platform member 12 and the base member 11, respectively, which are moving relative to each other in opposite directions. Therefore, the linear member 14A is prone to rolling relative to the base member 11 and the loading platform member 12. This rolling is not restricted by the loading platform member 12 because the hole in the loading platform member 12 through which the shaft portion 14a of the linear member 14A is inserted is an elongated hole 12h that extends in the first horizontal direction DH1. Furthermore, as already explained, the load of the cargo 100 acts on the loading platform member 12 and the linear member 14A, so the linear member 14A is pressed against the rail 13. Therefore, the loading platform member 12 moves relative to the base member 11 in the first horizontal direction DH1 while maintaining the state in which the contact portion 14, which is the linear member 14A, is pressed against and in contact with the upper surface 13c (upper surface) of the rail 13.

[0034] As already explained, the rail 13 is provided such that its upper surface 13c extends in the first horizontal direction DH1, and the rail surface of the rail 13 is formed such that, when viewed from the second horizontal direction DH2, the upper surface 13c is recessed downward in an arc shape. Therefore, when the relative movement described above occurs, the contact portion 14, the loading platform member 12, and the load 100 perform a pendulum motion that traces an arc-shaped trajectory based on the arc shape of the rail surface, causing the loading platform member 12 (and the load 100) to move relative to the base member 11 in the first horizontal direction DH1. At this time, the horizontal component of the force generated by the relative movement of the load 100 and the loading platform member 12 is input from the contact portion 14 to the rail surface, which is formed in an arc shape and is angled with respect to the first horizontal direction DH1. In this way, the vibration damping device 10 suppresses the vibration of the rack 1 by applying a force to the base member 11 and the rack 1 in the opposite direction to the direction in which the load 100 and the loading platform member 12 tend to vibrate and displace via the rail 13. The relative movement between the base member 11 and the cargo bed member 12, as described above, is damped by the damper 17.

[0035] Considering that the vibration damping device 10 suppresses vibrations by applying a force to the rack 1 in the opposite direction to the direction of the rack's displacement as described above, it is desirable that the period of the pendulum motion in the vibration damping device 10 be adjusted to a value close to the natural period of the rack 1 in the first horizontal direction DH1. Here, if we let L be the radius of the pendulum motion and g be the acceleration due to gravity, the period T of the pendulum's oscillation can be expressed by the following equation (1).

number

[0036] For example, when constructing a vibration damping device for the above-described vibration system using mass and a spring, if the spring constant is k and the mass is m, the period can be expressed as shown in equation (2) below.

number

[0037] From the viewpoint of efficiently suppressing vibrations of the rack 1, it is desirable to install the vibration damping device 10 described above in a concentrated manner on one or more levels located above the rack 1, where the displacement will be greater when vibrations occur. Furthermore, as described above, although the period T of the pendulum motion of the vibration damping device 10 is configured not to depend on the mass of the cargo 100, for the cargo platform member 12 to move relative to the base member 11 due to inertial force, it is necessary that cargo 100 with a certain mass be placed on the cargo platform member 12. Therefore, in a system operating an automated warehouse, when deciding which storage space S of rack 1 to store the cargo 100 in, it is desirable to prioritize selecting a storage space S equipped with the vibration damping device 10 and to store the cargo 100 there.

[0038] The vibration damping device 10 (10A, 10B) described above is a vibration damping device 10 (10A, 10B) that is attached to a rack 1 capable of storing luggage 100, and comprises a base member 11 attached to a support member 6 (6A, 6B) of the rack 1 that extends in a first horizontal direction DH1 and supports the luggage 100 from below, a loading platform member 12 provided above the base member 11 on which the luggage 100 is placed, and a rail 13 fixed to the base member 11 and provided to extend in a first horizontal direction DH1, with the rail surface formed such that when viewed from a second horizontal direction DH2 perpendicular to the first horizontal direction DH1, the upper surface 13c is recessed downward in an arc shape, and the loading platform member 12 is provided with a contact portion 14 (linear member 14A) that contacts the rail surface from above, and the loading platform member 12 is provided so as to be movable relative to the base member 11 in the first horizontal direction DH1 while maintaining the state in which the contact portion 14 contacts the rail surface. In the configuration described above, the rack 1 is equipped with a support member 6 extending in the first horizontal direction DH1, and the vibration damping device 10 is equipped with a base member 11 attached to the support member 6 and a loading platform member 12 provided above the base member 11. In this configuration, the cargo 100 is placed on the loading platform member 12, and the load of the cargo 100 is transmitted to the support member 6 via the loading platform member 12 and the base member 11, so that the cargo 100 is supported from below by the support member 6. In addition to the above configuration, the vibration damping device 10 includes a rail 13 fixed to the base member 11, extending in the first horizontal direction DH1, with a rail surface formed on its upper surface 13c, and the loading platform member 12 includes a contact portion 14 that contacts the rail surface from above. Furthermore, the loading platform member 12 is provided so as to be movable relative to the base member 11 in the first horizontal direction DH1 while maintaining the state in which the contact portion 14 contacts the rail surface. Therefore, when an earthquake or the like occurs and the rack 1 vibrates in the first horizontal direction DH1, the base member 11 attempts to move in the first horizontal direction DH1 together with the support member 6, while the loading platform member 12 and the load 100 placed on it move relative to the base member 11 in the first horizontal direction DH1 due to inertial force. In this way, the load 100 acts as a mass body, and a force opposite to the response speed of the rack 1 is applied from the load 100 to the rack 1, thereby damping the vibration of the rack 1. Here, the rail surface of the rail 13 is formed such that, when viewed from the second horizontal direction DH2 which is perpendicular to the first horizontal direction DH1, the upper surface 13c is curved downward in an arc shape. Therefore, when an earthquake or the like occurs and the rack 1 vibrates in the first horizontal direction DH1, the loading platform member 12 moves relative to the base member 11 while the contact portion 14 remains in contact with the rail surface. As a result, the loading platform member 12 and the load 100, which is a mass placed on the loading platform member 12, perform a pendulum motion based on the arc shape of the rail surface. The period of this pendulum motion does not depend on the mass of the load 100, but is determined only by the radius of the pendulum motion. In other words, no matter what mass the load 100 has when placed on the loading platform member 12, the period of movement of the load 100 can be kept constant. Therefore, by adjusting the radius of the pendulum motion to roughly synchronize the period of movement of the load 100 with the natural period of the first horizontal direction DH1 of rack 1, it is possible to achieve a state in which vibration damping performance is effectively demonstrated. In this way, it becomes possible to realize a vibration damping device 10 that can be attached to the rack 1 and exhibit good vibration damping performance regardless of the mass of the load 100 placed on it.

[0039] Furthermore, the vibration damping device 10 can obtain a stable period regardless of the weight of the stored items. In addition, the vibration damping device 10 has a simple structure and can be easily attached to the support member 6 (rack 1), making it easy to install.

[0040] Furthermore, the first horizontal direction DH1 is the depth direction of the rack 1, and when the rack 1 vibrates in the first horizontal direction DH1, the loading platform member 12 moves relative to the base member 11 so as to reciprocate in the first horizontal direction DH1, and the radius of curvature of the rail surface is set so that the reciprocating period is approximately equal to the natural period of the rack 1 in the first horizontal direction DH1. Rack 1 is more prone to vibration in the depth direction, which is shorter in length than in the width direction. With the above configuration, the first horizontal direction DH1 is the depth direction of rack 1, and when rack 1 vibrates in the first horizontal direction DH1, the loading platform member 12 moves relative to the base member 11 so as to reciprocate in the first horizontal direction DH1. Therefore, the vibration damping device 10 can efficiently suppress vibrations of rack 1 in the depth direction. Furthermore, since the radius of curvature of the rail surface is set such that the reciprocating period described above is approximately equal to the natural period of rack 1 in the first horizontal direction DH1, for example, between 80% and 120% of the natural period, the period of the vibration damping device 10 is roughly synchronized with the natural period of rack 1 in the depth direction. Therefore, the vibration damping device 10 can suppress vibrations of rack 1 in the depth direction even more efficiently.

[0041] Furthermore, the vibration damping device 10 is further equipped with a damper 17 interposed between the base member 11 and the cargo bed member 12 to dampen the relative movement between the base member 11 and the cargo bed member 12. With the above configuration, the relative movement between the base member 11 and the cargo bed member 12 can be appropriately dampened.

[0042] Furthermore, the support member 6 is formed to have a rectangular shape when viewed from the first horizontal direction DH1, the base member 11 comprises an upper plate 11c and side plates 11e extending downward from each of the opposite ends of the upper plate 11c in the second horizontal direction DH2, and is placed over the support member 6 from above so that the support member 6 is sandwiched between the side plates 11e, and the cargo bed member 12 comprises an upper plate 12c and side plates 12e extending downward from each of the opposite ends of the upper plate 12c in the second horizontal direction DH2, and is placed over the base member 11 from above so that the base member 11 is sandwiched between the side plates 12e. Furthermore, an elongated hole 12h extending in the first horizontal direction DH1 is formed in the side plate 12e of the cargo bed member 12, and a linear member 14A is inserted through the elongated hole 12h as a contact portion 14 so as to extend in the second horizontal direction DH2, and the linear member 14A is placed on the rail surface. With the configuration described above, the vibration damping device 10 can be properly implemented.

[0043] (Analysis example) Next, we will describe the analysis performed on the vibration damping device 10 of the above embodiment. Figure 9 shows a model for performing seismic response analysis on a rack equipped with the vibration damping device of the above embodiment. First, as an embodiment, a model M was prepared that simulates a rack 1 with the vibration damping device 10 of the above embodiment mounted on a support member 6. This model M has a configuration with 17 layers, and the vibration damping device 10 is installed on the top three layers. In the layers where the vibration damping device 10 is installed, the rack mass M1 is connected to the pallet mass M4 via a shear spring M2 that simulates a rail and a dashpot M3, and the cargo body mass M5, which has a value of 500 kg, is connected to the pallet mass M4 via a shear spring M6 that simulates the friction between the pallet 101 and the cargo body 102. In this embodiment, the period of the vibration damping device 10 is synchronized with the natural period of the rack 1 (1.68 s). In floors where the vibration damping device 10 is not provided, the rack mass M1 is connected to the pallet mass M4 via a shear spring M7 that simulates the friction between the support member 6 and the pallet 101, and the cargo body mass M5, which is set to a value of 500 kg, is connected to the pallet mass M4 via a shear spring M6 that simulates the friction between the pallet 101 and the cargo body 102. In contrast, as Comparative Example 1, a model was prepared in which, at all levels, the rack mass M1 is connected to the pallet mass M4 via a shear spring M7 that simulates the friction between the support member 6 and the pallet 101, and the cargo body mass M5, set to a value of 500 kg, is connected to the pallet mass M4 via a shear spring M6 that simulates the friction between the pallet 101 and the cargo body 102. Furthermore, as Comparative Example 2, a model was prepared that had a similar configuration to Model M of the Example, but with a period of 1.18s for the vibration damping device 10, which was not synchronized with the natural period of the rack 1. Furthermore, seismic response analyses were performed on these three types of models.

[0044] Figure 10 is a graph showing the response acceleration of each layer of the rack, based on the results of seismic response analysis performed on the model shown in Figure 9. Figure 11 is a graph showing the relative displacement of the pallets in each layer of the rack, based on the results of seismic response analysis performed on the model shown in Figure 9. Figure 12 is a graph showing the response acceleration acting on the cargo placed on the pallets in each layer of the rack, based on the results of seismic response analysis performed on the model shown in Figure 9. These graphs show that when the vibration damping device 10 of the above embodiment is used, a certain vibration damping effect is achieved even if the periods are not precisely synchronized, compared to when it is not used. Furthermore, it can be seen that a more favorable effect is obtained when the periods are adjusted compared to when they are not adjusted.

[0045] (Modified example of Embodiment 1) Next, a first modified example of the above embodiment will be described. Figure 13 is a longitudinal cross-sectional view of the vibration damping device according to this modified example. The vibration damping device 10C of this modified example is attached to the support member 6 of the rack 1, similar to the vibration damping device 10 of the above embodiment. Here, as with the above embodiment, the vibration damping device 10C provided on the support member 6A located on the left side when viewed from the front side FS will be described. The vibration damping device provided on the support member 6B located on the right side will not be described, as it has a structure symmetrical to the vibration damping device 10C, similar to the above embodiment. The vibration damping device 10C of this modified example is equipped with a base member 11, a loading platform member 12, a rail 13, and a damper 17, similar to the vibration damping device 10 of the above embodiment.

[0046] In this modified example, the base member 11 has the same configuration as the base member 11 in the above embodiment, but with a sliding material 13k made of polytetrafluoroethylene or the like attached to the surface of the side plate 11e above the position where the rail 13, which will be described later, is provided. In the above embodiment, the cargo bed member 12 had an elongated hole 12h in the side plate 12e. However, in this modified example, the cargo bed member 12 has a circular hole 12j in the same position as the elongated hole 12h in the embodiment, instead of the elongated hole 12h. The rail 13 in this modified example has the same shape as the rail 13 in the above embodiment. In this modified example, the upper surface 13c, which forms the rail surface, is positioned at an intermediate height in the vertical direction DV of the side plate 11e of the base member 11 and is joined to the side plate 11e. The damper 17 in this modified example has the same configuration as the damper 17 in the above embodiment.

[0047] The loading platform member 12 is provided with a contact portion 14 that abuts against the rail surface of the rail 13. In this modified example, the contact portion 14 is a threaded bearing 14B. The threaded bearing 14B comprises a bearing portion 14c and a shaft portion 14d. The bearing portion 14c is formed to be circular when viewed from the second horizontal direction DH2. The thickness of the bearing portion 14c is slightly thinner than that of the rail 13. The shaft portion 14d is provided at the center of the bearing portion 14c, passing through the bearing portion 14c and protruding from the center of the bearing portion 14c in only one direction in the second horizontal direction DH2. A thread is provided on the outer circumference of this protruding portion of the shaft portion 14d. Inside the bearing portion 14c, a plurality of bearings (not shown) are interposed between the bearing portion 14c and the shaft portion 14d, and the bearing portion 14c is rotatable relative to the shaft portion 14d via these bearings.

[0048] The male threaded bearing 14B described above is provided such that the bearing portion 14c is located between the side plate 11e of the base member 11 and the side plate 12e of the loading platform member 12, and the shaft portion 14d is screwed into the hole 12j from the inside of the loading platform member 12. A spring washer 14e is interposed between the bearing portion 14c and the side plate 12e of the loading platform member 12. The threaded bearing 14B is placed on the upper surface 13c of the rail 13 and is in contact with the upper surface 13c. The surface of the bearing portion 14c opposite to the shaft portion 14d is positioned to face the sliding material 11k attached to the side plate 11e of the base member 11.

[0049] In this modified example, the vibration damping device 10 operates in the same manner as in the above embodiment. In other words, with respect to the vibration damping device 10C as described above, the cargo 100 is placed on the upper plate 12c of each of the loading platform members 12 of the vibration damping device 10C. In the vibration damping device 10C, the load of the cargo 100 is transmitted to the support member 6 in order via the loading platform members 12 and contact parts 14, rails 13, and base members 11.

[0050] When an earthquake occurs and the rack 1 equipped with the vibration damping device 10C described above vibrates in the first horizontal direction DH1, the support member 6, the base member 11, and the rail 13 are displaced in the first horizontal direction DH1. On the other hand, the loading platform member 12 and the load 100, due to their inertial force, attempt to move relative to the base member 11 in the first horizontal direction DH1, in the opposite direction to the direction in which the base member 11 is attempting to move.

[0051] Here, the loading platform member 12 is mounted on the rail 13 via a contact portion 14, i.e., a threaded bearing 14B, which has a circular bearing portion 14c. The bearing portion 14c is rotatably mounted relative to a shaft portion 14d fixed to the loading platform member 12. Forces acting in opposite directions in the first horizontal direction DH1 act on the shaft portion 14d and the bearing portion 14c of the threaded bearing 14B, respectively, due to the loading platform member 12 and the base member 11, which are moving relative to each other in opposite directions. Therefore, the bearing portion 14c rotates on the rail surface of the rail 13 relative to the shaft portion 14d. Furthermore, as already explained, the load of the cargo 100 acts on the loading platform member 12 and the threaded bearing 14B, so the threaded bearing 14B is pressed against the rail 13. Therefore, the loading platform member 12 moves relative to the base member 11 in the first horizontal direction DH1 while maintaining a state in which the contact portion 14, which is a male threaded bearing 14B, is pressed against the upper surface 13c (rail surface) of the rail 13.

[0052] Similar to the above embodiment, the rail 13 is provided such that its upper surface 13c extends in the first horizontal direction DH1, and the rail surface of the rail 13 is formed such that, when viewed from the second horizontal direction DH2, the upper surface 13c is recessed downward in an arc shape. Therefore, when performing the relative movement described above, the contact portion 14, the loading platform member 12, and the load 100 perform a pendulum motion that traces an arc-shaped trajectory based on the arc shape of the rail surface, causing the loading platform member 12 (and the load 100) to move relative to the base member 11 in the first horizontal direction DH1. Through this relative movement, the vibration damping device 10C suppresses vibrations of rack 1 by applying a force to rack 1 in the opposite direction to the direction in which the load 100 is vibrating and displaced. The relative movement between the base member 11 and the cargo bed member 12, as described above, is damped by the damper 17. In this modified vibration damping device 10C, as in the above embodiment, the period T for the reciprocating pendulum motion can be set as a fixed value, regardless of the mass of the load 100 placed on the loading platform member 12. For this reason, no matter what mass of load 100 is stored, the period of the vibration system is synchronized with the natural period of the rack 1, making it possible to always efficiently suppress the vibration of the rack 1.

[0053] (Second modified example of the embodiment) Next, a second modified example of the above embodiment will be described. Figure 14 is a plan view of the vibration damping device according to this modified example. Figure 15 is a schematic longitudinal cross-sectional view of the vibration damping device provided on the left side in Figure 14. Figure 16 is a side view of the vibration damping device provided on the left side in Figure 14, as viewed from the side of the luggage storage space (the right side in Figure 14). Figure 17 is a cross-sectional view of the area indicated by the arrow IV-IV in Figure 15. The vibration damping device 10D of this modified example is attached to the support member 6 of the rack 1, similar to the vibration damping device 10 of the above embodiment. Here, as with the above embodiment, the vibration damping device 10D provided on the support member 6A located on the left side when viewed from the front side FS will be described. The vibration damping device 10E provided on the support member 6B located on the right side will not be described, as it has a structure symmetrical to the vibration damping device 10D, similar to the above embodiment. The vibration damping device 10D of this modified example comprises a base member 11, a loading platform member 12, a rail 13, and a damper 17, similar to the vibration damping device 10 of the above embodiment.

[0054] The base member 11 in this modified example has substantially the same configuration as the base member 11 in the above embodiment. In this modified example, the damper fixing member 11i is provided on the surface of the side plate 11e. In the cargo bed member 12 of the above embodiment, the side plate 12e is formed only in the portion where the damper fixing member 12i and the contact portion 14, which will be described later, are provided. The side plate 12e has a circular hole 12j in the portion where the contact portion 14 is provided. In this modified example, a non-slip material 12k such as rubber is provided on the upper surface of the top plate 12c to suppress slippage between it and the cargo 100 (more specifically, the pallet 101). The rail 13 in this modified example has the same shape as the rail 13 in the above embodiment. In this modified example, the upper surface 13c, which forms the rail surface, is positioned at an intermediate height in the vertical direction DV of the side plate 11e of the base member 11 and is joined to the side plate 11e. The damper 17 in this modified example has the same configuration as the damper 17 in the above embodiment.

[0055] The loading platform member 12 is provided with a contact portion 14 that abuts against the rail surface of the rail 13. In this modified example, the contact portion 14 is a sliding mechanism 14C that is fixed to the side plate 12e of the loading platform member 12 and slides against the rail surface of the rail 13. The sliding mechanism 14C comprises a support portion 14f and a sliding material 14g. The support portion 14f is formed of, for example, steel. The support portion 14f is fixed to the inside of the side plate 12e by a bolt 14h that penetrates the hole 12j of the side plate 12e from the outside. The sliding material 14g is fixed to the lower end of the support portion 14f. The sliding material 14g is made of polytetrafluoroethylene or the like. The sliding mechanism 14C described above is mounted so as to be slidable in the first horizontal direction DH1, with the sliding material 14g in contact with the upper surface 13c of the rail 13.

[0056] In this modified example, the vibration damping device 10 operates in the same manner as in the above embodiment. In other words, with respect to the vibration damping device 10D as described above, the cargo 100 is placed on each of the loading platform members 12 of the vibration damping device 10D. In the vibration damping device 10D, the load of the cargo 100 is transmitted to the support member 6 in order via the loading platform members 12 and contact parts 14, rails 13, and base members 11.

[0057] When an earthquake occurs and the rack 1 equipped with the vibration damping device 10D described above vibrates in the first horizontal direction DH1, the support member 6, the base member 11, and the rail 13 are displaced in the first horizontal direction DH1. On the other hand, the loading platform member 12 and the load 100, due to their inertial force, attempt to move relative to the base member 11 in the first horizontal direction DH1, in the opposite direction to the direction in which the base member 11 is attempting to move. Here, the loading platform member 12 is configured to be slidable on the rail 13 in the first horizontal direction DH1 via the contact portion 14, i.e., the sliding material 14g of the sliding mechanism 14C. Furthermore, since the load of the cargo 100 acts on the loading platform member 12 and the sliding mechanism 14C, the sliding mechanism 14C is pressed against the rail 13. Therefore, the loading platform member 12 moves relative to the base member 11 in the first horizontal direction DH1 while maintaining the state in which the contact portion 14 of the sliding mechanism 14C is pressed against the upper surface 13c (rail surface) of the rail 13.

[0058] Similar to the above embodiment, the rail 13 is provided such that its upper surface 13c extends in the first horizontal direction DH1, and the rail surface of the rail 13 is formed such that, when viewed from the second horizontal direction DH2, the upper surface 13c is recessed downward in an arc shape. Therefore, when performing the relative movement described above, the contact portion 14, the loading platform member 12, and the load 100 perform a pendulum motion that traces an arc-shaped trajectory based on the arc shape of the rail surface, causing the loading platform member 12 (and the load 100) to move relative to the base member 11 in the first horizontal direction DH1. Through this relative movement, the vibration damping device 10D suppresses the vibration of rack 1 by applying a force to rack 1 in the opposite direction to the direction in which the load 100 is vibrating and displacing. The relative movement between the base member 11 and the cargo bed member 12, as described above, is damped by the damper 17. In this modified vibration damping device 10D, as in the above embodiment, the period T for the reciprocating pendulum motion can be set as a fixed value, regardless of the mass of the load 100 placed on the loading platform member 12. For this reason, no matter what mass of load 100 is stored, the period of the vibration system is synchronized with the natural period of the rack 1, making it possible to always efficiently suppress the vibration of the rack 1.

[0059] (Third modified example of the embodiment) Next, a third modified example of the above embodiment will be described. This modified example is a further modification of the second modified example. Figure 18 is an enlarged view of the main part of the vibration damping device according to the third modified example. In this modified vibration damping device 10F, the rail 13 and the contact portion 14 are configured in a way that the vertical direction DV is reversed compared to the configuration of the vibration damping device 10D in the second modified example described above. More specifically, the rail 13 is fixed to the loading platform member 12. In this modified example, the rail 13 is fixed to the underside of the upper plate 12c of the loading platform member 12. The rail 13 is provided to extend in the first horizontal direction DH1, and when viewed from the second horizontal direction DH2, the rail surface is formed such that the underside 13d is recessed upward in an arc shape. In this modified example, the base member 11 is provided with a contact portion 14. In this modified example, the contact portion 14 is fixed to the side plate 11e of the base member 11 and is provided to contact the rail surface, i.e., the lower surface 13d, of the rail 13 from below. The contact portion 14 in this modified example is a sliding mechanism 14C similar to that in the second modified example, and includes a support portion 14f and a sliding material 14g. The support portion 14f is fixed to the side plate 11e by a bolt 14h. The sliding material 14g is fixed to the upper end of the support portion 14f. As described above, the rail 13 is slidably mounted on the contact portion 14 in the first horizontal direction DH1 so that its lower surface 13d contacts the sliding material 14g.

[0060] The vibration damping device 10F described above is a vibration damping device 10F that is attached to a rack 1 capable of storing luggage 100, and comprises a base member 11 attached to a support member 6 (6A, 6B) of the rack 1 that extends in a first horizontal direction DH1 and supports the luggage 100 from below, a loading platform member 12 provided above the base member 11 on which the luggage 100 is placed, and a rail 13 fixed to the loading platform member 12 and provided to extend in a first horizontal direction DH1, with a rail surface formed such that when viewed from a second horizontal direction DH2 perpendicular to the first horizontal direction DH1, the lower surface 13d is recessed upward in an arc shape, the base member 11 has a contact portion 14 that contacts the rail surface from below, and the loading platform member 12 is provided so as to be movable relative to the base member 11 in the first horizontal direction DH1 while maintaining a state in which the rail surface contacts the contact portion 14 of the base member 11. In the configuration described above, the rack 1 is equipped with a support member 6 extending in the first horizontal direction DH1, and the vibration damping device 10F is equipped with a base member 11 attached to the support member 6 and a loading platform member 12 provided above the base member 11. In this configuration, the cargo 100 is placed on the loading platform member 12, and the load of the cargo 100 is transmitted to the support member 6 via the loading platform member 12 and the base member 11, so that the cargo 100 is supported from below by the support member 6. In addition to the above configuration, the vibration damping device 10F includes a rail 13 fixed to the loading platform member 12, extending in the first horizontal direction DH1, with a rail surface formed on its lower surface 13d, and the base member 11 includes a contact portion 14 that contacts the rail surface from below. Furthermore, the loading platform member 12 is provided so as to be movable relative to the base member 11 in the first horizontal direction DH1 while maintaining the state in which the rail surface contacts the contact portion 14 of the base member 11. Therefore, when an earthquake or the like occurs and the rack 1 vibrates in the first horizontal direction DH1, the base member 11 attempts to move in the first horizontal direction DH1 together with the support member 6, while the loading platform member 12 and the load 100 placed on it move relative to the base member 11 in the first horizontal direction DH1 due to inertial force. In this way, the load 100 acts as a mass body, and a force opposite to the response speed of the rack 1 is applied from the load 100 to the rack 1, thereby damping the vibration of the rack 1. Here, the rail surface of the rail 13 is formed such that, when viewed from the second horizontal direction DH2 which is perpendicular to the first horizontal direction DH1, the lower surface 13d is curved upward in an arc shape. Therefore, when an earthquake or the like occurs and the rack 1 vibrates in the first horizontal direction DH1, the contact portion 14 of the base member 11 remains in contact with the rail surface, and the loading platform member 12 moves relative to the base member 11. As a result, the loading platform member 12 and the load 100, which is a mass placed on the loading platform member 12, perform a pendulum motion based on the arc shape of the rail surface. The period of this pendulum motion does not depend on the mass of the load 100, but is determined only by the radius of the pendulum motion. In other words, no matter what mass the load 100 has when placed on the loading platform member 12, the period of movement of the load 100 can be kept constant. Therefore, by adjusting the radius of the pendulum motion to roughly synchronize the period of movement of the load 100 with the natural period of the first horizontal direction DH1 of rack 1, it is possible to achieve a state in which vibration damping performance is effectively demonstrated. In this way, it becomes possible to realize a vibration damping device 10F that can be attached to the rack 1 and exhibit good vibration damping performance regardless of the mass of the load 100 placed on it.

[0061] It should be noted that the vibration damping device of the present invention is not limited to the embodiments and modifications described above with reference to the drawings, and various other modifications are conceivable within its technical scope. For example, the third modified example was described as a configuration in which the rail 13 and the contact portion 14 of the second modified example are reversed overall in the vertical direction DV. Similarly, in the above embodiment and the first modified example, the rail 13 and the contact portion 14 may also be configured in which the overall direction DV is reversed overall. Furthermore, the number of components such as the elongated holes 12h, contact portions 14, and rails 13 is not limited to those described in the above embodiment and each modified example. It goes without saying that any number of components can be provided as long as the vibration damping device 10 operates stably. In addition to the above, it is possible to select or discard the configurations listed in the above embodiments and their respective modifications, or to change them to other configurations as appropriate. [Explanation of symbols]

[0062] 1. Rack 14A Linear member (contact part) 6, 6A, 6B Support members; 14B Male threaded bearing (contact part) 10, 10A~10F Vibration damping device 14C Sliding mechanism (contact part) 11 Base member 17 Damper 12 Cargo bed components 100 Cargo 13 Rail DV Vertical Direction 13c Top surface (rail surface) DH1 First horizontal direction (depth direction) 13d Bottom surface (rail surface) DH2 2nd horizontal direction 14 Contact part

Claims

1. A vibration damping device that can be attached to a rack capable of storing luggage, A base member attached to a support member of the rack that extends in a first horizontal direction and supports the load from below, A loading platform member is provided above the base member on which the cargo is placed, A rail is fixed to the base member and is provided so as to extend in the first horizontal direction, and when viewed from a second horizontal direction perpendicular to the first horizontal direction, the rail surface is formed such that the upper surface is recessed downward in an arc shape, Equipped with, The aforementioned cargo bed member is provided with a contact portion that contacts the rail surface from above, The cargo bed member is provided so as to be movable relative to the base member in the first horizontal direction while maintaining a state in which the contact portion is in contact with the rail surface. A vibration damping device characterized by the following features.

2. A vibration damping device that can be attached to a rack capable of storing luggage, A base member attached to a support member of the rack that extends in a first horizontal direction and supports the load from below, A loading platform member is provided above the base member on which the cargo is placed, A rail is fixed to the cargo bed member and is provided so as to extend in the first horizontal direction, and when viewed from a second horizontal direction perpendicular to the first horizontal direction, the rail surface is formed such that the lower surface is recessed upward in an arc shape, Equipped with, The base member is provided with a contact portion that contacts the rail surface from below, The cargo bed member is provided so as to be movable relative to the base member in the first horizontal direction, while maintaining a state in which the rail surface is in contact with the contact portion of the base member. A vibration damping device characterized by the following features.

3. (Corresponding to draft claim 2) The first horizontal direction is the depth direction of the rack, When the rack vibrates in the first horizontal direction, the loading platform member moves relative to the base member so as to reciprocate in the first horizontal direction. The radius of curvature of the rail surface is set such that the reciprocating period is approximately equal to the natural period of the rack in the first horizontal direction. The vibration damping device according to claim 1 or 2.

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